Infrared Remote control transmitters Circuits

This is the Infrared Remote control transmitter circuit. It has high performance and can be applied to works with the various infrared receiver circuit. To made easily and best to save your money.

I want not to tell you much, what is the infrared remote control. Because you have known as well. So I recommend circuits 2 types, as appropriate.

  • The first is a simple circuit. The Infrared light from a section to a section to work immediately.
  • Then other circuits are designed to have wider applications. They can be set programs of a beam of infrared light to circuits.

Let’s get started.

The basic infrared remote control transmitter

Usually, when we apply a DC voltage to the infrared diode. It works but we cannot see the beam light with the naked eye.

You can find this infrared LED on Amazon here if you’re interested.

But in real applications, we need to power it with a pulse signal at a frequency of about 5kHz. Because of eliminating the various noise and reduce the power supplied to them.

See in the first circuits. It is a simple infrared transmitter circuit using 555 timers. We use it as It is an oscillator generator at a frequency of 5kHz. that is set with R1, R2 and C2.

Schematic Diagram of Simple infrared transmitter (Before improve)

The output signal will have a period on-off is 1:1 or we called 50% duty cycle.
The resistor R3 is used to limit current flow through the infrared diode under 50mA.

Improved circuits

Previously, I used this circuit, but Mihai introduced new device configuration principles. I agree And thank you for the useful advice. We should improve the circuit.

  • We want a LED, gets the current average approx 50mA. If we use a 9V battery at 68 ohms, it uses current about 132mA. And if the output is a square wave 50% duty cycle. So, the current of LED is 60mA (approx).
  • Change C1 is 0.0033uF for output about 5kHz.

The shopping list

  • IC1: 555 timer
  • R1: 3.9K
  • R2: 47K
  • C1: 0.0033uF 50V Ceramic
  • Infrared LED

If you want the infrared transmitter that has the signal strength is very high. You can be done by adding the output transistors. Enable With the infrared diodes up to three tubes.


High Power Infrared Remote Control Transmitter Circuit

Be seen from the circuit, IC 555 use to function frequency generator is 5000Hz as well. The frequency of the circuit is determined by the VR1, R1, R2 and C1, we can customize the frequency by adjusting VR1.

Output of IC is supplied to the transistor Q1-BD137 to drive infrared diodes with high current to 100mA. Risisetars R3 in the circuit should not be less than 3.9 ohm as it may cause damage to TR1. R4 and LED1 to indicate that the voltage supply to the circuits.

Small Infrared transmitters circuit using LM3909

This is an infrared transmitters signal circuit that is small size and using a power supply 1.5V only. by main electronic part are two the LM3909 (a LED Flasher Oscillator IC) Normally, we tend to put it to use as a simple flashing light circuit. Using a 1.5V low power supply, it’s working now, Easier to use transistors. The high frequency, it is very simple, just change the device to high frequency only. C1 and R1 is lower the higher frequency.

Small Infrared transmitters circuit using LM3909

Small Infrared transmitters circuit using LM3909

Related Posts


I always try to make Electronics Learning Easy.

This Post Has 2 Comments

  1. Be aware that the current through IR LED is limited to about 136mA(if R3=68Ω) and not 50mA. The usual term for the “signal period on-off” is called “DUTY CYCLE” and in this case is about 0.52 or 52%. Anyway, this duty cycle is too much. Try to lower it, say 10% or less. It’s good for the LEDs.

    What formula did you use to compute the output frequency? With those values the frequency is about 3.13Hz(the period is 0.3189sec). In order to obtain the desired freq.(5kHz) you should use 3nF(0.003µF) for C2 instead of 4.7µF.

    Now, for the second diagram…

    …R3 should not be less than 3.9 ohm… I think you meant R4!

    You don’t need an electrolytic cap. for C2. A poliester cap will do the job brilliantly. R1 should be no less than 5kΩ. 470Ω is way too low. Check the application note AN170 regarding NE555 for a proper design. Like that one above, the duty cycle is too much(>50%). Lowering the duty cycle while maintaining the frequency unchanged will reduce the power consumption. In
    this instance R4(5.6Ω) dissipates around 8Watt, so BEWARE!!!

  2. Wonderful web site…great projects …keep it up!

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Close Menu